<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .box{
            width: 300px;height: 300px;background: pink;margin: 100px auto;
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
<script>
    const obox =document.querySelector(".box")
    // 状态库（字典量）
    let DATE = {
        hidden:Symbol(),
        show:Symbol()
    }
    // 默认初始状态状态
    let flag=DATE.hidden;

    document.onclick=function(){
        if(flag==DATE.hidden){
            obox.style.display="none";
            flag=DATE.show;
        }else{
            obox.style.display="block";
            flag=DATE.hidden;
        }
    }
</script>
</html>